Tamiya 70189 Mini Motor Low-Speed Gearbox (4-Speed) Kit

Tamiya’s 4-speed low-speed mini motor gearbox features a more compact 030-form-factor brushed DC motor driving a single gear train that can be assembled to have one of four gear ratios: 71.4:1, 149.9:1, 314.9:1, or 661.2:1. The gear train includes a self-locking worm gear.

Overview

The mini-motor gearbox kit from Tamiya makes it easy to get a small robot or plastic model moving. The kit includes one brushed DC motor and all the gears and parts to build any of the four possible gear ratio configurations: 71.4:1, 149.9:1, 314.9:1, or 661.2:1. The four gear ratio options give you the flexibility to choose the best speed and torque for your project.

The gear train of the low-speed gearbox includes a self-locking worm gear, which means the gear train can not be back-driven (the motor can spin the output axle in both directions, but you cannot turn the output axle with your hand). Not being able to back-drive the gear train is useful when powering vehicles that stop on steep inclines, or when powering mechanisms that lift heavy objects off the ground (like gates or drawbridges).

The kit includes step-by-step illustrated instructions in both Japanese and English. A scanned copy of the instructions is available on the Pictures tab. The kit can be built with just a screwdriver, but the instructions recommend having side cutters, tweezers, and a modeling knife on hand. The gearbox kit’s motor has a 030 form factor that is smaller than the Tamiya gearboxes that use the Mabuchi FA-130 motor.